A great number of substances for the effective treatment of inflammatory illnesses, for example rheumatism, have been known for a long time. Since the inflammations are often chronic, the treatment with such inflammation-preventing active substances will usually extend over a long period of time. The non-steroidal antiphlogistic substances used for such continuous treatments very often have undesirable side effects on the digestive tract, such as, for example, in the form of gastro-intestinal bleeding and stomach ulcers as described by Y. H. Lee et al in "Arch. int. Pharmacodyn." 191, 370-377 (1971) and by K. D. Rainsford in "Agents and Actions" 1977 7(5/6), 573-77, as well as by A. R. Cooke in "Drugs" 1976, vol. 11, pages 36 to 44.
Many attempts have been made to moderate the side effects of these effective non-steroidal antiphlogistic substances by the admixture of an additional active substance. All mixtures of this type have the disadvantage that the additional substance might cause an ulcer on its own, or might even influence adversely the effectiveness of the primary non-steroidal antiphlogistic substance.
Attempts have been made, for example, to admix anticholinergic substances or pepsin inhibitors with the antiphlogistic substances (Y. H. Lee et al, "Arch. int. Pharmacodyn," 191, 370 -377 (1971)). The firm of Richter Gedeon (DE-OS 25 24 902) proposed the admixture of salicylic acid salts with the antiphlogistic substances. However, salicylic acid salts have analgetic and antiphlogistic properties of their own and can cause strong side effects such as nausea and vomiting as well as damage of the mucous membrane of the stomach with the possibility of bleeding if administered over longer periods of time as reported by E. Mutschler in "Arzneimittelwirkungen", wissenschaftliche Verlagsgesellschaft 1970, pages 76, 77.
The Sumitomo Chemical Co. Ltd. has proposed the combination of non-steroidal antiphlogistic substances with quinazolines (see DE-OS 26 27 914) with the purpose of preventing the formation of peptic ulcers within the area of the digestive tract. However, these quinazolines are substances with an analgetic and antiphlogistic effect of their own. U.S. Pat. No. 3,993,767 describes mixtures of non-steroidal antiphlogistic substances with metaxalon. However, the metaxalon has a muscle-relaxing effect. See the Merck Index, Ninth edition 1976, page 772.